The present invention relates to an ink cartridge to be coupled to a device using ink.
Conventionally, ink cartridges have been widely used in devices using ink. An example of such devices, an inkjet printing device has been known. The inkjet printing device typically includes an inkjet head, which has an ink nozzle. The ink nozzle is driven to eject ink drops toward recording medium such as a piece of paper to form images and characters thereon. Typically, the ink cartridge includes an ink reservoir, and the ink accommodated in the reservoir is supplied to the inkjet head.
The exchangeable ink cartridge is advantageous in that when the printer runs out of the ink, only by replacing the old cartridge with a new cartridge. Therefore, the exchangeable ink cartridge is widely employed.
A typical structure of the ink cartridge is configured such that an ink reservoir is formed inside a housing of the cartridge, and an opening formed on the housing. The reservoir is connected with a communication path, and the opening is sealed with a stopper such as a rubber stopper.
The device, to which the ink cartridge is to be coupled, is formed with an ink cartridge bay, where a hollow needle is projected at a position corresponding to the rubber stopper. When the ink cartridge is coupled to the cartridge bay, the hollow needle penetrates through the rubber stopper so that the ink can be sucked via the communication path and the hollow needle and supplied to the device.
In a case of an inkjet printer, the hollow needle is connected with an inkjet head through an ink feed tube so that the ink is supplied from the ink cartridge to the inkjet head.
If air or impurities invade inside the reservoir, bubbles of the air and/or the impurities are supplied to the device together with the ink, which may cause trouble. For example, if the device is an inkjet printer, and if the bubbles are supplied to the printer, some dots may not be formed since drops of ink is not jetted due to the bubbles. The impurities supplied to the printer may block up the ink nozzles.
Therefore, a structure which is capable of preventing the air and impurities from invading in the device when the ink is supplied from the replaceable ink cartridge to the device is desired.
However, in view of manufacturing such an ink cartridge, it is desired that an operation for filling the reservoir with the ink is relatively easy. Further, once the reservoir is filled with the ink, invasion of the air and/or impurities should be blocked without fail.